<?php
// we will do our own error handling
//error_reporting(0);

// user defined error handling function
function userErrorHandler($errno, $errmsg, $filename, $linenum, $vars) 
{
   // timestamp for the error entry
   $dt = date("Y-m-d H:i:s (T)");

   // define an assoc array of error string
   // in reality the only entries we should
   // consider are E_WARNING, E_NOTICE, E_USER_ERROR,
   // E_USER_WARNING and E_USER_NOTICE
   $errortype = array (
               E_ERROR              => 'Error',
               E_WARNING            => 'Warning',
               E_PARSE              => 'Parsing Error',
               E_NOTICE             => 'Notice',
               E_CORE_ERROR         => 'Core Error',
               E_CORE_WARNING       => 'Core Warning',
               E_COMPILE_ERROR      => 'Compile Error',
               E_COMPILE_WARNING    => 'Compile Warning',
               E_USER_ERROR         => 'User Error',
               E_USER_WARNING       => 'User Warning',
               E_USER_NOTICE        => 'User Notice',
               E_STRICT             => 'Runtime Notice',
               E_RECOVERABLE_ERROR  => 'Catchable Fatal Error'
               );
   // set of errors for which a var trace will be saved
   $user_errors = array(E_USER_ERROR, E_USER_WARNING, E_USER_NOTICE);
   
   $err = "<errorentry>\n";
   $err .= "\t<datetime>" . $dt . "</datetime>\n";
   $err .= "\t<errornum>" . $errno . "</errornum>\n";
   $err .= "\t<errortype>" . $errortype[$errno] . "</errortype>\n";
   $err .= "\t<errormsg>" . $errmsg . "</errormsg>\n";
   $err .= "\t<scriptname>" . $filename . "</scriptname>\n";
   $err .= "\t<scriptlinenum>" . $linenum . "</scriptlinenum>\n";

   if (in_array($errno, $user_errors)) {
       $err .= "\t<vartrace>" . wddx_serialize_value($vars, "Variables") . "</vartrace>\n";
   }
   $err .= "</errorentry>\n\n";
   
   // for testing
   // echo $err;

   // save to the error log, and e-mail me if there is a critical user error
   error_log($err, 3, "/usr/local/php4/error.log");
   if ($errno == E_USER_ERROR) {
       mail("phpdev@example.com", "Critical User Error", $err);
   }
}


function distance($vect1, $vect2) 
{
   if (!is_array($vect1) || !is_array($vect2)) {
       trigger_error("Incorrect parameters, arrays expected", E_USER_ERROR);
       return NULL;
   }

   if (count($vect1) != count($vect2)) {
       trigger_error("Vectors need to be of the same size", E_USER_ERROR);
       return NULL;
   }

   for ($i=0; $i<count($vect1); $i++) {
       $c1 = $vect1[$i]; $c2 = $vect2[$i];
       $d = 0.0;
       if (!is_numeric($c1)) {
           trigger_error("Coordinate $i in vector 1 is not a number, using zero", 
                           E_USER_WARNING);
           $c1 = 0.0;
       }
       if (!is_numeric($c2)) {
           trigger_error("Coordinate $i in vector 2 is not a number, using zero", 
                           E_USER_WARNING);
           $c2 = 0.0;
       }
       $d += $c2*$c2 - $c1*$c1;
   }
   return sqrt($d);
}

$old_error_handler = set_error_handler("userErrorHandler");

// undefined constant, generates a warning
$t = I_AM_NOT_DEFINED;

// define some "vectors"
$a = array(2, 3, "foo");
$b = array(5.5, 4.3, -1.6);
$c = array(1, -3);

// generate a user error
$t1 = distance($c, $b) . "\n";

// generate another user error
$t2 = distance($b, "i am not an array") . "\n";

// generate a warning
$t3 = distance($a, $b) . "\n";

?>